After the head swap, my astra has been playing up a bit. At about 2.5k rpm the car gets really jerky and you have to put your foot down to pull through it. It also does it around 2.5k on over run. I'm wondering if it's an ignition lead playing up?
As I'm running tb's I've adjusted the tps but it's still the same. Do you think it could be that the mapping's out now as the head is not as ported as the old head??